Millions of people living with type 2 diabetes rely on medication to control their blood sugar.
But new research suggests that some of the most common diabetes drugs might actually increase the risk of serious heart problems.
Scientists at Northwestern University have found that two widely used treatments—sulfonylureas and basal insulin—can significantly raise the risk of heart attacks, strokes, and heart failure.
Type 2 diabetes happens when the body doesn’t use insulin properly, leading to high blood sugar levels over time. If left untreated, it can cause damage to blood vessels, nerves, and organs.
The first drug doctors usually prescribe for diabetes is metformin, which helps lower blood sugar and improve how the body uses insulin. However, many people eventually need a second medication when metformin alone no longer works. This is where sulfonylureas and basal insulin often come in.
Sulfonylureas work by helping the pancreas release more insulin. Basal insulin, also known as long-acting insulin, is used to keep blood sugar stable throughout the day and night. These drugs have been trusted treatments for years, but the new study shows they may not be as safe as once thought, especially for the heart.
The Northwestern researchers analyzed data from more than 132,000 adults with type 2 diabetes who needed to start a second medication after metformin. Their study is one of the first to directly compare how major second-line diabetes drugs affect heart health in real-life patients rather than just in controlled clinical trials.
The results were eye-opening. People taking sulfonylureas were 36% more likely to experience a serious heart event—such as a heart attack, stroke, or heart failure—than those who took a newer type of drug called DPP-4 inhibitors.
The risk was even higher for people taking basal insulin. They were found to be twice as likely to develop these dangerous heart problems compared with those using DPP-4 inhibitors.
The researchers broke the numbers down further. For every 37 people who took basal insulin for two years, one had a major cardiovascular event.
For those taking sulfonylureas, one event occurred for every 103 people over the same period. When you think about the 30 million Americans living with type 2 diabetes, these numbers translate to a large potential impact on public health.
The study’s lead author, Dr. Matthew O’Brien, said the results should be a wake-up call for both doctors and patients. He believes the findings show a need to rethink how type 2 diabetes is treated after metformin stops working. “We need to focus on prescribing drugs that not only control blood sugar but also protect the heart,” he explained.
Newer diabetes drugs, such as GLP-1 agonists, SGLT-2 inhibitors, and DPP-4 inhibitors, have been shown to be safer for the heart and may even reduce cardiovascular risk.
The problem is that these newer options are often much more expensive, making them less accessible to many patients. As a result, doctors often continue prescribing older drugs like sulfonylureas and basal insulin because they are cheaper and more familiar.
Still, the researchers argue that the long-term benefits of avoiding heart attacks and strokes could outweigh the higher upfront cost of newer medications. Heart disease is already the leading cause of death among people with diabetes, so preventing even a small number of cases could save lives and reduce healthcare costs in the long run.
This study, published in JAMA Network Open, sends a clear message: people with type 2 diabetes should talk to their doctors about their treatment options.
Understanding the potential heart risks of certain medications is just as important as managing blood sugar levels. For some, switching to a newer drug may offer better protection for both their heart and overall health.
If you care about diabetes, please read studies about bananas and diabetes, and honey could help control blood sugar.
For more health information, please see recent studies about Vitamin D that may reduce dangerous complications in diabetes and results showing plant-based protein foods may help reverse type 2 diabetes.
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